package com.example.home7;

import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;


public class SQLite extends Fragment {
    private dbHelper dbHelper;
    public SQLite() {
        super(R.layout.sqljiemian);
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        dbHelper = new dbHelper(getContext());
        EditText e1 = getView().findViewById(R.id.textView3);
        EditText e2 = getView().findViewById(R.id.textView5);
        TextView textView = getView().findViewById(R.id.textView6);
        getView()
        .findViewById(R.id.button6)
        .setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SQLiteDatabase database = dbHelper.getWritableDatabase();
                ContentValues values = new ContentValues();
                values.put("username", e1.getText().toString());
                values.put("age", e2.getText().toString());
                Toast.makeText(getActivity(),
                        database.insert("users", null, values) == -1?
                        "添加失败" : "添加成功",
                        Toast.LENGTH_SHORT).show();
                database.close();
                textView.setText(showDbDate(null));
            }
        });
        getView()
        .findViewById(R.id.button7)
        .setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                textView.setText(showDbDate("age < 18"));
            }
        });
    }
    private String showDbDate(String selection) {
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        Cursor cursor = database.query("users",null,selection,null,null,null,null);
        StringBuilder stringBuilder = new StringBuilder();
        while(cursor.moveToNext()){
            stringBuilder
                    .append("id:")
                    .append(cursor.getLong(cursor.getColumnIndex("id")))
                    .append("    username:")
                    .append(cursor.getString(cursor.getColumnIndex("username")))
                    .append( "   age:")
                    .append(cursor.getLong(cursor.getColumnIndex("age")))
                    .append("\n");
        }
        return stringBuilder.toString();
    }
}
